XL VIII ] 



PITYITES 



375 



Geological Survey I have been able to examine the sections in the 

 Jermyn Street Museum. Graf Solms-Laubach describes the leaves 

 as oval in section, the upper face strongly convex and the lower 

 almost flat as m two-needled Pines, but as shown in fig. 774, A the 

 leaves may be approximately cylindrical (1 mm. in diameter), like 

 those of Pinus monophylla or the leaves of Cedrus. There is a single 

 vein accompanied by some radially disposed transfusion-tracheids, 

 the whole being enclosed in a single layer of rather thick-walled 



FIG. 773. Pityites Solmsi. (British Museum, V. 2146; nat. size.) 



cells. There is no distinct division of the bundle into two halves 

 but there are indications of the presence of a broad median medul- 

 lary ray. The mesophyll-cells have prominent infoldings precisely 

 as in recent Pines, Cedrus, and some other Abietineae (fig. 774, B; 

 cf. fig. 694): the epidermis has a thick cuticle and below it are 

 1 2 layers of small thick-walled elements. Solms-Laubach speaks 

 of two resin-canals, one at each side of the lamina, but I was unable 

 to distinguish any undoubted canals in the leaf shown in fig. 774, 

 The occasional absence of canals in Abietineous leaves normally 



